With the increasing use of robotics and other automation, more and more mechanical fabrication and assembly operations are performed by machines. In many cases, some degree of compliance is necessary or desirable in preforming many machine tasks.
As one simple example, consider the task of applying a label to a workpiece. A label is positioned on a mechanical extender, such as a tool attached to a robotic arm, such that an adhesive surface is facing outwardly, and a workpiece is positioned in front of it. The arm then simply extends until it makes contact with the workpiece, and the label adheres to the workpiece. However, if the workpiece facing surface is not precisely aligned with a plane normal to the axial direction of the arm extension—that is, if the workpiece surface is skew to plane of the label—only an edge, or even just a corner, of the label will be pressed against the workpiece surface. If, on the other hand, the tool applying the label has even a slight degree of skew compliance, a uniform force will be applied over the entire surface of the label, even if the facing surface of the workpiece is not perfectly perpendicular to the axis of motion of the arm.
In general, mechanical loads may require compliance in numerous aspects, such as skew (two planes not perfectly parallel), axial (along the line of motion), transverse (perpendicular to the line of motion), rotational, or more generally, some combination of these. Prior art mechanical tools and couplings conventionally do not allow for mechanical compliance, or are compliant only in one aspect. Furthermore, prior art tools and couplings that do provide for mechanical compliance, such as via springs and the like, have only one “stiffness,” and cannot adapt to the different levels of compliance force that are encountered in various robotic applications.
The Background section of this document is provided to place embodiments of the present invention in technological and operational context, to assist those of skill in the art in understanding their scope and utility. Unless explicitly identified as such, no statement herein is admitted to be prior art merely by its inclusion in the Background section.